Transparent materials having high conductivity are required for touch panels, antistatic agents and other electronic members.
A method commonly adopted for providing such conductive materials is one using vapor deposition of indium tin oxide (ITO) on a substrate made of a PET film or the like. However, the method of vapor-depositing the ITO layer requires a large-scale device and involves comparatively high costs. In addition, in the case of using for a variety of packaging materials as in deep drawing using vacuum forming, for example, the ITO layer could not follow the deformation of the substrate, causing cracks.
An exemplary general-purpose conductive polymer material is polyaniline, but polyaniline is very high in cohesive force and extremely low in dispersibility in solvents, and has therefore had difficulty in striking a good balance between uniformity/transparency with which it can be applied to the film and conductivity.
A process for producing a dispersible, intrinsically conductive polyaniline powder is known in which the polyaniline powder is sheared in the presence of a polar solvent leading to increased conductivity (see Patent Document 1).
A method of producing a conductive path by arranging very thin fibrils of a conductive polymer has been come up with in order to strike a good balance between transparency and conductivity, and a large number of literatures have recently been reported on the conductive polymer in the form of nanofibers (see for example Non-Patent Document 1). Non-Patent Document 1 describes that fibrillar polyaniline is obtained by polymerizing aniline in a stationary state at the interface between an organic solvent and water.    Patent Document 1: JP 3583427 B    Non-Patent Document 1: Xinyu Zhang, Roch Chan-Yu-King et al., “Nanofiber of polyaniline synthesized by interfacial polymerization”, Synthetic Metals, 145 (2004), 23-29.